The invention relates to a data deletion device for magnetic tapes, in particular computer tapes.
Magnetic tapes, in particular computer tapes, usually comprise a so-called recognition code at their start which extends always over a known tape length.
Because of legal requirements or because of other demands, it is often necessary to delete the data on a magnetic tape in such a complete manner that no residual or partial information remains on the data carrier (tape) after deletion. On the other hand, however, it is frequently necessary or desirable that the said recognition code at the start of the tape remains undeleted.
Deletion devices are known in which the magnetic tape is rewound completely and is guided past a clearing head during rewinding. This method is very time-consuming and thus expensive. Furthermore, deletion devices are known in which relative movement occurs between a coil (choke) and a reel transversely to the plane of the reel. Admittedly these devices operate rapidly and reliably, but on the other hand, however, the entire information comprised on the tape, inclusive of the recognition code, is deleted.